Add debugprintf rust shader

Author: LegNeato

shaders/rust/Cargo.toml

@@ -70,6 +70,7 @@ members = [
     "occlusionquery/mesh",
     "occlusionquery/occluder",
     "computeheadless/headless",
+    "debugprintf/toon",
 ]
 
 [workspace.dependencies]

shaders/rust/debugprintf/toon.frag.spv

@@ -0,0 +1,13 @@
+[package]
+name = "debugprintf-toon"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+spirv-std = { workspace = true }
+
+[lib]
+crate-type = ["dylib"]
+
+[package.metadata.rust-gpu.build]
+extensions = ["SPV_KHR_non_semantic_info"]

shaders/rust/debugprintf/toon.vert.spv

@@ -0,0 +1,100 @@
+#![cfg_attr(target_arch = "spirv", no_std)]
+#![feature(asm_experimental_arch)]
+#![allow(clippy::missing_safety_doc)]
+
+use spirv_std::{
+    glam::{vec3, vec4, Mat3, Mat4, Vec3, Vec4},
+    macros::debug_printf,
+    num_traits::float::Float,
+    spirv,
+};
+
+#[repr(C)]
+pub struct UBO {
+    projection: Mat4,
+    model: Mat4,
+    light_pos: Vec4,
+}
+
+#[spirv(vertex)]
+pub fn main_vs(
+    #[spirv(vertex_index)] _vertex_index: i32,
+    in_pos: Vec3,
+    in_normal: Vec3,
+    in_color: Vec3,
+    #[spirv(uniform, descriptor_set = 0, binding = 0)] ubo: &UBO,
+    #[spirv(position)] out_position: &mut Vec4,
+    out_normal: &mut Vec3,
+    out_color: &mut Vec3,
+    out_view_vec: &mut Vec3,
+    out_light_vec: &mut Vec3,
+) {
+    *out_normal = in_normal;
+    *out_color = in_color;
+    *out_position = ubo.projection * ubo.model * vec4(in_pos.x, in_pos.y, in_pos.z, 1.0);
+
+    let pos = ubo.model * vec4(in_pos.x, in_pos.y, in_pos.z, 1.0);
+
+    // Output the vertex position using debug printf
+    unsafe {
+        debug_printf!("Position = %v4f", pos);
+    }
+
+    let model_mat3 = Mat3::from_cols(
+        ubo.model.x_axis.truncate(),
+        ubo.model.y_axis.truncate(),
+        ubo.model.z_axis.truncate(),
+    );
+
+    *out_normal = model_mat3 * in_normal;
+    let l_pos = model_mat3 * ubo.light_pos.truncate();
+    *out_light_vec = l_pos - pos.truncate();
+    *out_view_vec = -pos.truncate();
+}
+
+#[spirv(fragment)]
+pub fn main_fs(
+    in_normal: Vec3,
+    in_color: Vec3,
+    in_view_vec: Vec3,
+    in_light_vec: Vec3,
+    #[spirv(descriptor_set = 0, binding = 1)] _sampler_color_map: &spirv_std::Image!(2D, type=f32, sampled),
+    out_frag_color: &mut Vec4,
+) {
+    // Desaturate color
+    let gray = in_color.x * 0.2126 + in_color.y * 0.7152 + in_color.z * 0.0722;
+    let desaturated = vec3(gray, gray, gray);
+    let color = in_color.lerp(desaturated, 0.65);
+
+    // High ambient colors because mesh materials are pretty dark
+    let ambient = color;
+    let n = in_normal.normalize();
+    let l = in_light_vec.normalize();
+    let v = in_view_vec.normalize();
+    let r = (-l).reflect(n);
+
+    let diffuse = n.dot(l).max(0.0) * color;
+    let specular = r.dot(v).max(0.0).powf(16.0) * vec3(0.75, 0.75, 0.75);
+
+    let base_color = ambient + diffuse * 1.75 + specular;
+    *out_frag_color = vec4(base_color.x, base_color.y, base_color.z, 1.0);
+
+    // Toon shading
+    let intensity = n.dot(l);
+    let mut shade = 1.0;
+    if intensity < 0.5 {
+        shade = 0.75;
+    }
+    if intensity < 0.35 {
+        shade = 0.6;
+    }
+    if intensity < 0.25 {
+        shade = 0.5;
+    }
+    if intensity < 0.1 {
+        shade = 0.25;
+    }
+
+    let final_color = in_color * 3.0 * shade;
+    *out_frag_color = vec4(final_color.x, final_color.y, final_color.z, 1.0);
+}